Method for refining petroleum hydrocarbons



Patented Nov. 6, 1951 METHOD FOR REFINING PETROLEUM HYDROCARBON S Alexander Greentree, Nacogdoches, Tex., and

Donald A. Hermanson, Plainfield, N. J., assignors to Socony-Vacuum Oil Company, Incorporated, a corporation of New York No Drawing. Application June 4, 1949, Serial No. 97,324

This invention relates to a method for refining mineral oils and waxes and, more particularly, is directed to a process for contacting petroleum and various fractions thereof with a solid, porous sorbent material under conditions hereinafter described to yield a product of improved characteristics.

The process contemplated by the present in- Claims. (01. 196-147) vention provides a new method for refining mineral oils andwaxes by contacting the oil or wax with a solid, porous sorbent material under such conditions that oil is sorbed into the pores of the contact material. The porous material con- .taining sorbed oil is then heated to an elevated temperature and arefined oil is thereafter separated from the pores of the sorbent.

The method of this invention may be employed in refining petroleum hydrocarbons generally, it being only necessary that the charge stock undergoing treatment enter the pores of the sorbent material and remain in intimate contact therewith during the maintenance of said material'at an elevated temperature. Thus, the process described herein may be used in refining both residual and distillate petroleum stocks. The process of this invention may further be used in conjunction with deasphalting and dewaxing of petroleum fractions. The method may also be employed with advantage in treating partially re- I fined stocks, such as those whichhave previously been deasphalted, dewaxed, acid-treated, solvent-refined, and thelike. f

A porous, solid contact material is used as the sorbent medium in the present process. The particular contact material employed may be either one having no selective sorbing action for specific components making up the charge stock, or the contact material may exhibit/a selective sorbing action for certain components of the stock, while leaving other components unsorbed. As will be shown hereinafter, either type of sorbent may be advantageously employed in the present process. The latter type of contact material, however, is to be preferred, since a greater refining action is generally obtained with the use thereof. A particularly preferred embodiment of the present invention involves the use of a sorbent contact material having the ability to sorb the less viscous, low molecular volume components of the charge stock, leaving the more viscous, high molecular volumecomponents unsorbed. When the sorbent employed is one having no selective sorbing action for specific components making up thechargestock, its composition should generally besuch that it'catalytically promotes conversion, such as reforming or mild cracking, of the oil sorbed within its porous structure.

Porous contact materials having a substantially uniform structure of low macropore volume, with an average pore diameter not exceeding about 125 angstrom units and a particle size not smaller than about 60 mesh, have the ability for most operations to sorb the low viscosity, light colored components of the petroleum hydrocarbon fraction undergoing treatment, while leaving substantially unsorbed the darker, more viscous components. The macropore volume of the contact material preferred for use in the process of this invention should be relatively low so that the pore volume is substantially that of micropores. In general, the volume of macropores, i. e., those pores having radii larger than about angstrom units, should constitute less than about 30 per cent of the total volume, and preferably 10 per cent or less.

The particle size of the particular sorbent employed in the process of this invention is, to some extent, dependent on the variables involved in application of the process. These important variables are: time of contact between the petroleum hydrocarbon fraction under treatment and the sorbent in the sorption zone, temperature in the sorption zone, viscosity of the liquid charge, and, to a lesser extent, the ratio of liquid mixture to sorbent charged to the sorption zone. Increasing the time of contact results in a decrease of the efiiciency of the desired separation. Decreasing viscosity of the liquid charge has the same effect. On the other hand, increasing temperature and decreasing viscosity both result in a more rapid sorption of the lighter, less viscous components of the hydrocarbon mixture. If the ratio of sorbent to liquid charge is excessive, some loss in separation eificiency results. By proper control of the aforementioned variables, some latitude in the average diameter of the sorbent particles employed may be permitted. However, when the diameter of the particles becomes too small, the sorbent preferably sorbs the heavier, more viscous components from the charge mixture, leaving the lighter, less viscous components unsorbed.

In general, it may be said that the particle size of the sorbent material should be not less than about 60 mesh Tyler and preferably Within the range of about 0.022 to about 1 inch average diameter. The greatest selective separation was "observed; with sorbents having a particle size not less than'about30mesh,-particularly within the 3 range of 0.03 to 0.20 inch average diameter and of reasonably uniform size. It is pointed out, however, that by proper control of the variables discussed hereinabove and also of the average pore diameter of the sorbent, operation according to the method of this invention may be obtained on sorbent particles outside the ranges given, although the results will, in general, be less satisfactory, since the selective action of the sorbent is thereby decreased. It is contemplated,

however, that in its broader aspects, this invention covers the use of sorbents having little or no selective action, as well as the useof a sorbent having a pore and particle size within the specified preferred limits.

The porosity of the sorbent particles employed in the process of this invention is generally reflected in the bulk density, the lower the bulk density the greater being the degree of porosity. For purposes of the present process, porous sorbent particles having bulk densities of between about 0.4 and about 1.1 grams per cubic centimeter are preferred. The bulk densities indicated correspond to an average pore diameter between about 20 and about 125 angstrom units. Preferably, the sorbent used will have a bulk density between about 0.6 and about 0.8 gram per cubit centimeter. The particles of higher density will, in general, produce a greater degree of refining but they will have a lower'sorbing capacity. Particles of a lower bulk density, on the other hand, have a relatively greater sorbing capacity but a lesser degree of selectivity. The choice of a sorbent of any particular density will, in general, depend upon the viscosity of the charge stock and degree of refining desired.

The degree of porosity of the particular sorbent contact material used will, in general, depend on the conditions under which it is prepared. A particularly convenient and effective sorbent for use in the present process is one made up of inorganic oxide gel particles prepared by the process described in U. S. Patent 2,384,946, issued September 18, 1945, to Milton M. Marisic. It is there disclosed that spheroidal particles of inorganic oxide gel may be prepared by mixing an acidic stream with a stream of sodium silicate and allowing the resulting hydrosol to be ejected from a nozzle into an oil column, where the gel sets in the form of bead-like spheroids. The resulting gel spheres, after washing, drying and tempering, were of a size varying between about 4 and about 20 mesh. The gel beads so produced had a bulk density of between about 0.4 and about 1.1 and an average pore diameter of between about 20 and about 125 angstrom units.

It is likewise contemplated that irregularly shaped porous sorbent fragments may be used in the present process. However, in general, spheroidal particles, particularly those of an inorganic oxide gel, are to be preferred, since attrition losses are then at a minimum and contamination with gel fines of the petroleum stock being treated is substantially eliminated.

In general, inorganic oxide gel particles, such as those of silica, zirconia, alumina, beryllia, thoria, and the like, will be used inthe process of this invention. Of this group, the siliceous gel particles containing silica, either alone or in combination with one or more other inorganic metal oxides, are preferred. Thus, particles of silica gel, silica-alumina gel, silica-zirconia gel, silica-thoria gel, and the like are excellent sorbents for use in the'pr'esent process. It is also contemplated that within t he scopeof this invention, other porous materials not of inorganic oxide gel composition, such as synthetic siliceous compositions and porous pelleted clays, may also be employed in the method of this invention.

The process is, accordingly, carried out by bringing a petroleum fraction to be refined in contact with a porous sorbent medium, preferably having the characteristics described above, heating the sorbent medium containing sorbed oil to an elevated temperature and thereafter removing the sorbed oil from the pores of the sorbent material. The contacting is carried out in a suitable vessel, where direct contact between particles of sorbent and the mixture to be treated is efiected. In the instance where the sorbent employed exerts a selective action for certain components of the charge stock, the lower molecular volume components will enter the pores of the sorbent, while the higher molecular components remain unsorbed. Where the sorbent used is one exerting no preferential sorption action, the charge stock will enter the pores of the sorbent as such and the sorbent particles will eventually become saturated with said stock.

The temperature at which the contacting step is conducted may vary over wide limits, depending to a large extent on the nature of the particular petroleum fraction being treated. The minimum usable temperature is, in general, the lowest temperature at which the liquid component of lowest freezing point will flow. The maximum temperature at which the sorption process can be carried out is usually governed by the viscosity of the mixture being treated. The sorption becomes less selective as the viscosity of the mixture decreases. Thus, where the mixture being separated is a mineral oil fraction, the lowest temperature usable is that at which the oil will flow, and the maximum temperature will be dependent on the viscosity of the fraction being separated. For a distillate stock, the maximum temperature may be below room temperature, while a heavy residual stock can be treated at temperatures as high as about 350 F.

The time required for the sorption process to take place depends upon the conditions of contact, such as the viscosity of the mixture being treated, temperature, and the like. In general, saturation of the sorbent particles with the mixture is not required and too long a contact time is to be avoided, since it has generally been found to reduce the overall selectivity of the operation.

The weight ratio of sorbent to the mixture undergoing treatment may vary over wide limits but will generally be between about 0.1 to 1 and about 20 to 1, and preferably between 0.5 and 3. The higher ratios will usually be employed with the sorbents of higher density which exhibit a lower sorbing capacity.

The sorbent particles containing sorbed oil are, in accordance with'the process of this invention, subjected to an elevated temperature generally greater than about 200 F., by maintaining the sorbed oil in intimate contact with the sorbent at elevated temperature, refining of said oil takes place, accompanied by mild cracking and reforming reactions. The maximum temperature to which the sorbent containing sorbed oil is subjected should be less than that at which active cracking occurs and, in general, should not exceed about 600 F. The heat treatment of the sorbent containing sorbed oil may vary from a period of less than one hour up to several hours, depending upon the degree of refining desired and the particular petroleum stock being treated.

in general, the period of heat treatment is such as to effect an appreciable refining of the'sorbed oil. Under usual operating conditions, the duration of heat treatment will ordinarily be between about 1 and about 5 hours.

The subsequent removal of the sorbed oil from the pores of the contact material may be effectively accomplished by a solvent extraction procedure. The solvent employed may be one having a preferential selectivity for particular. components of the sorbed oil or the solvent may be characterized .by little selectivity, in which case the oil removed by solvent extraction will be substantially the same as that contained in the pores of the contact material. 'Aromatichydrocarbon V be refined through a bed of the porous sorbent.

The following detailed examples will serve to illustrate the process of this invention without limiting the same:

EXAMPLE 1 A silica-alumina hydrosol was prepared by mixing 1.00 volume of a solution of sodium silicate containing 157.0 grams of SiOz per liter with 1.00

alcohols, ketones, esters, aldehydes, and the like also show a selectivity for particular components of the sorbed oil. However, with the use of these solvents, the selectivity is the reverse of that obtained with paraffinic solvents; that is, the material extracted by the polar solvent is a fraction of relatively high viscosity and high carbon residue as compared with that of the sorbed oil. When the sorbed oil is removed from the pores of the contact material by a selective solvent extraction procedure, either a parafiinic or a polar solvent may be employed as the initial solvent, followed by treatment with a solvent of the opposite type to remove remaining sorbed components. Thus,

when a polar solvent is employed as the initial r mainder of the sorbed oil is thereafter preferably removed by extraction with a second, more polar solvent, notably a ketonic solvent containing a normally liquid ketone, such as methyl ethyl ke- 'volume of a solution containing 39.79 grams of aluminum sulfate and 30.51 grams of sulfuric acid per liter. The resulting colloidal solution was ejected from a nozzle in the form of globules into a column of gas oil whose depth was about 8 feet. The globules of solution fell through the oil and gelled before passing into a layer of water located beneath the oil. The time of gelation for the concentrations and proportions of reactants given above was about 4 seconds. The spherical particles of gel were conducted out of the bottom of the column into a stream of water and, on removal from the water, were base exchanged with an aqueous solution of aluminum sulfate and water-washed. The globules were then slowly and uniformly dried in superheated steam at about 300 F. until shrinkage was substantially complete, and the drying was continued at a gradually increasing temperature up to about 1050 F., which temperature was maintained for 0.5 hours. The silica-alumina gel resulting retained its spheroidal shape during the washing and drying operations and had a final particle size of about 4-20 mesh. The bulk density of particles so obtained was between about 0.4 and about 1.1 grams per cubic centimeter and the average pore diameter was between about 20 and about 125 angstrom units. 1

A quantity of about 780 grams of an East Texas residuum, having a viscosity of 512 seconds at tone, acetone, methyl isopropyl ketone, and the like. The parafiinic extract of oil removed from the sorbent is generally characterized by a low a carbon residue, whereas the oil removed with the ketonic solvent has a relatively higher carbon residue and can be recycledfor further contact with the sorbent or withdrawn as a by-product.

fraction. The solvent so employed, both the primary parafiinic solvent and the secondary polar solvent, can be recovered upon separation from the refined oil and re-used in the process.

After extraction ofthe oil from the sorbent, the

210 F. (Saybolt Universal viscosity) and a carbon residue of 11.1 per cent, which had previously been contacted with the above described sorbent particles to remove a portion of the oil constituents therefrom, and 9'7 grams of the untreated residuum were percolated through 200 grams of the above prepared gel particles for 4 hours at 275 F. Approximately the first 17 grams of material to drain from the gel particles constituted an asphaltic product. About 56 grams of unsorbed oil were then washed from the surface of the gel particles by applying 400 cubic centimeters of acid-treated Stoddard solvent at a temperature of 275 F. The gel particles containing sorbed oil were then subjected to a heat treatment at a temperature of 350 F. for one hour. The heat treated particles containing sorbed oil were then extracted with five portions of 150 cubic centimeters each of normal hexane at a temperature of 150 F., permitting one-half hour contact with each solution. As a result of this extraction, 61 grams of a low carbon residue oil were obtained. The remaining sorbed oil was then extracted from the pores of the gel particles at a temperature of 160 F. with three portions of cubic centimeters each of a mixture consisting of equal volumes of methyl ethyl ketone and Stoddard solvent, permitting one-half hour contact with each portion. About 15 grams of a high carbon residue product were recovered by this extraction.

Several experiments were made using the general procedure outlined in the above example, except that the time and temperature of the heat from each cycle was tested separately. The data obtained show that the gel particles used in this process can be regenerated for a number of cycles by simply drying and steaming. They can also be burned occasionally to completely restore their original efficiency. The results of the aforementioned experiments are shown in the table below:

Table 11 Example l ll 12 13 l4 l 16 Heat Treatment:

Time, Hours 3 3 3 3 3 3 0 Temperature, F. 350 350 350 350 350 350 Cycle No. on Beads 1 2 3 4 5 1 l-fi Selective Extraction:

Solvent Hexane Hexane Hexane Hexane Hexane Hcxane Hexane Temperature, F 150 150 Deasphalted Oil, Yi

residuum) 62. 8 56.0 51.4 52. 3 53. 4 55.2 54. 6 Dewaxed Oil:

Yield, Per Cent Wt. (based on dcasphalted oil).. 70. 5 72.2 73. 7 71. 3 73. 5 72. 2 71. 9

Inspections:

S. U. V. at 210 F., Seconds 137.0 138.8 135.5 144.1 137. 9 138. 7 152 Viscosity Index -1 98 98 07 97 98 98 04 Color, Lovibond (34 cell) 200 185 220 205 210 204 400 Conradson Carbon Residue, Per Cent Wt... 1. 3 1. 3 1.1 1. 3 1. 3 1. 3 l. 6 Wax, Inspections: Color, Lovibond 04. cell) 79 87 90 100 95 90 170 1 Calculated average for 5 cycles. 1 Composite of 5 cycles with the heat treatment omitted. treatment step were varied. The 01]. obtained as EXAMPLE 17 a result of selective solvent extraction was referred to as deasphalted oil. This oil containing wax was then separated by conventional benzol-ketone treatment into dewaxed oil and wax. These experiments show that the oil recovered from a deasphalting operation which includes the step of heat treating the sorbent containing sorbed oil has a lighter color, a lower carbon residue, and a higher viscosity index than the pro-duct obtained in the absence of said heat treatment. The wax obtained from an oil which has been sorbed, heat treated and solvent-extracted in accordance with the above-described procedure likewise has a considerably ligher color than the product obtained without heat treatment. The results of these experiments are sum- An extract in the amount of 300 grams, obtained by counter current phenol extraction of a distillate stock having a Saybolt Universal viscosity of 68 seconds at 210 F., was contacted for one hour at 275 F. with 200 grams of gel particles having a bulk density of 0.602 and prepared as described in Example 1. The unsorbed material was drained ofi and the gel particles containing sorbed oil were given a quick wash with acid-treated Stoddard solvent at a temperature of 210 F. The gel particles containing sorbed oil were heat treated for 2 hours at 2'75 F. and then extracted with five portions, 150 cubic centimeters each, of normal hexane at a temperature of 150 F., allowing one-half hour for each pormarized m the table below: tion. Fifty-three grams of a light-colored 011 Table I Example 2 3 4 5 6 7 8 9 Heat Treatment:

Time, hours 0 3 1 3 10 3 0 4 Temperature, F 500 350 350 350 150 500 Selective Extraction:

Solvent Hexane Hexane Hexane Hexane Hexane Hexene (1) Temperature, F 150 150 150 150 150 245 240 Deasphalted Oil, Yield, per cent wt. (based 1 on residuum) 61 49 63 53 54 59 53 51 Dcwaxed Oil: Yield, per cent wt. (based on dcusplialtcd oil) 70 69 63 6B 67 74 Inspections:

S. U. V. at 210 F., seconds. 157 80. 8 139. 7 130. 4 131 2 139. 7 186 84.0 Viscosity Index 70 74 76 76 7 61 80 Color, Lovibond (54 cell).-. 300 43 78 75 185 750 215 Conradson Carbon Residue, p 1.6 0.5 1.1 0.8 0. 8 1.4 3. 2 1.3 Wax, Inspections:

Color, Lovibond (14 Cell) 125 20 64 45 60 105 450 70 Melting Point, F 165 164 165 164 164 165 164 rss 1 Acid treated Stoddard solvcnt. A further series of experiments was made on a 65 were recovered by this extraction. The material still remaining in the gel particles was then recovered by extracting with three portions, cubic centimeters each, of a'mixture consisting of equal volumes of methyl ethyl ketone and acid-treated Stoddard solvent at F. Sixteen grams of a black, viscous product were recovered by this extraction. The data obtained by this experiment, which illustrates application of the present process to prepare a lubricating oil from a material which would normally be use- 9 ful only as a fuel, are summarized in the table below:

Table III Untreated Charge Stock Absorption:

Gel Particle Density 0.602 Time, hours 1 Temperature, F 275 Heat Treatment:

Time, hours 2. Temperature, F 2 Selective Extraction:

Solvent Hexane Temperature, E 150 Yields, Per Cent Wt.:

Unabs Viscosity Index. Color, Lovibond (94" eel 1 Inspections on oil from first extraction.

EXAMPLE 18 Two 200-gram portions of 0.602 bulk density gel particles, prepared as described in Example 1, were contacted for one-half hour with 60 grams of microcrystalline wax at a temperature of 275 F. One portion was immediately extracted-using the extraction procedure described in the foregoing example. The other portion was heat treated for 3 hours at 380 F. before being extracted. The data from this experiment, which show that microcrystalline wax can be refined to produce a product of very light color, are summarized in the table below:

Table IV Untreated Heat Treatment:

EXAMPLE 19 Table V Untreated Charge Stock Heat Treatment:

. Time, hours 0 2 Temperature, F 350 Selective Extraction:

Solvent Hexane Hexane Temperature, F 150 150 Refined Oil:

Yield, Per Cent Wt. (based on de- 100 68.0 52. 4

asphalted residuum). Inspections:

S. U. V. at 210 F., Seconds..- 83.8 67.3 51.9 Color, Lovibond (54 Cell) 525 100 34 Conradson Carbon Residue, 1. 7 0.6 0. 2

Per Cent Wt. Dewaxed Oil:

Yield, Per Cent Wt. (based on re- 93. 0 91. 2 87. 9

fined oil) Inspections:

S. U. V. at 210 F., Seconds---- 85. 8 68.3 52.6 Viscosity Index 74 105 EXAMPLE 20 bulk density of 0.602. One sample was extracted immediately, using the extraction procedure de- Time, hoursn 0 3 scribed in Example 17. The second sample was gpgig ggigggg f heat treated for 3 hoursat 380 F. before being olvent Hexane Hexene extracted. Similar experiments were made, using figg t ggf F synthetic silica-alumina pellets and also using igud rer Cent Wt 100 82.2 84.8 clay pellets. The results of these experiments, f ig (W 460 150 6 which showed that all three ofthe contact ma- Meltmg'P01nt,F 142 147 141 terials exhibit refining action, are set forth 1n the table below:

Table VI Absorbent Unc i i s 11 id 1 P P em s thetic Silica- Stock tlcles of Silica- Clay Pellets Alumina Gel Alumina Pellets Heat Treatment:

Time, hours 0 3 0 3 0 3 s 1 'lemplesrajturrzi "F 380 380 380 6 1V6 X rec on:

Solvent Hexane Hexane Hexane. Hexane Hexane Hexane Temperature 150 150 150 150 150 150 Refined Product: v

135110111, 561' Cent Wt '83. O 81. 4 88.0 87. O 66. 0 65. 5

S 60 ODS:

s. U. v.@210 F., 120.8 101.4 84.6 101.1- 03.2 10.2 78.0 Viscosity Index 101 102 107 103 104 108 109 Color, Lovibond( 26 '14 12 9 4 3.2 Suliur,Per 00mm"..- 0. 50 0. 35 0.12 0. 34 0.14 0. 09 0. 05

:11 From the above examples, it will be apparent to those skilled in the art that the process of this invention can be employed in refining a variety of petroleum stocks. In all of the aforesaid examples, important refining action was observed.

While, as pointed out above, inorganic oxide gel particles of certain specified pore and particle size are preferably used in the process of this invention, since they afford a greater overall refining action due to their selective sorbing properties, it is to be understood that various other sorbent materials which do not exert any selecture in the liquid phase with a porous particle- 1.:

form contact material in which most of the pores are micropores and the volume of pores having radii greater than about 100 angstrom units is less than about per cent of the total pore volume and in which the particles are greater than about 60 mesh size to effect sorption of the less viscous, light-colored components of said mixture into the pores of said contact material. while leaving unsorbed the more viscous, darlicolored. components, separating the unsorbed components from the contact material containing sorbed components, heating said contact material containing sorbed components to an elevated temperature greater than about 200 F. but insuiiicient to cause appreciable cracking of the components sorbed therein and thereafter solvent-extracting said sorbed heat treated components from the pores of said contact material.

2. A process for refining a mineral oil, comprising sorbing the less iscous, light-colored comp nents of said oil into the pores of a substantially microporousparticle-form sorbent contact material, the particles of which .are greater than about 60 mesh and in which less than 30 per cent of the total pore volume is occupied bv pores having radii greater than about 100 angstrom units, while leaving unsorbed the more viscous, dark-colored components of said oil, removing said unsorbed components from the con-- heating said contact material containing sorbed components to an elevated temperature greater than about 200 .F. but below that temperature at which appreciable cracking of the sorbed components takes place and thereafter extracting the sorbed heat treated components with a parafiinic solvent to yield a refined oil of low carbonresidue, high viscosity index and light color.

3. A process for refining paraflin wax, comprising melting the wax, contacting the melted wax with a substantially macroporous sorbent contact material having a particle size not less than about 30 mesh and a total pore volume made up mostly of micropores, there being less than about 30 per cent of pores having radii greater than about angstrom units, whereby the low viscosity, light-colored components of said wax are sorbed into the pores of said contact material. while the high viscosity, dark-colored components remain unsorbed, separating said contact ma terial from said unsorbed components, heating said contact material containing sorbed components to an elevated temperature above the melting point of the wax but below about 600 F. and thereafter extracting the sorbed heat treated -12 wax components .irom the pores .of said contact material with a parafiinic solvent to yield a refined wax of light color.

4. A process for refining a petroleum hydrocarbon mixture, comprising contacting said mixture in the liquid phase with a porous particleform inorganic oxide gel contact material in which most of the pores are micropores and the volume of pores having radii greater than about 100 angstrom units is less than about 30 per cent of the total pore volume and in which the particles are greater than about 30 mesh size, whereby the less viscous, light-colored. components of said mixture are sorbed into the pores of said contact material, while leaving unsorbed the more viscous, dark-colored components, separating the unsorbed components from the contact material containing sorbed components, heating said contact material containing sorbed components to an elevated temperature between about 200 F. and about 600 F. and thereafter solvent-extracting the heat treated components from the pores of said contact material.

5. A process for refining a mineral oil, comprising contacting said oil with a uniiorm, substantially microporous contact material having a particle size not less than about 30 mesh and in which the volume of pores having radii greater than about 100 angstrom units is less than about 30 per cent of the total pore volume, whereby the low viscosity, light-colored components of said oil are sorbed into the pores of said contact material, while the high viscosity, dark-colored components remain unsorbed, separating said contact material from said unsorbed compon nts, heating said contact material containing sorbed components to an elevated temperature between. about 200 F. and about 600 F. and extracting the sorbed heat treated components with a paraffinic solvent to yield a refined oil of low carbon residue, high viscosity index and light color.

5. A process for refining a petroleum hydrocarbon mixture, comprising contacting said mixture in the liquid phase with a porous particleiorm contact material in which most of the pores are micropores and the volume of pores having radii greater than about 100 angstrom units is less than about 30 per cent of the total pore vol ume and in which the particles are greater than tact material containin b d component-,5, P about 30 mesh size to effect sorption of the less viscous, light-colored components of said mixture into the pores said contact material, while leaving unsorbed the more viscous, dark-colored components, separating the unsorbed components from the contact material containing sorbed components, washing adhering unsorbed components from the surface of said contact material, heating said contact material containing sorbed components to an elevated temperature greater than about 200 F. but below that temperature at which appreciable cracking of the sorbed components takes place and thereafter extracting the sorbed heat treated components with a paraflinic solvent to yield a refined petroleum hydrocarbon product.

'7. A process for "refining a mineral oil, comprising sor'oing the less viscous, light-colored components of said oil into the pores of a substantially microporous particle-form sorbent contact material, the particles of which are greater than about'fio' mesh size and in which less than 30 per cent of the total pore volume is occupied by pores having radii greater than about 100 angstrom units, while leaving unsorbed the more viscous, dark-colored components of said oil, removing said unsorbed components from the contact material containing sorbed components, heating said contact material containing sorbed components to an elevated temperature between about 200 F. and about 600 F., selectively extracting said contact material with a parafiinic solvent to remove therefrom a refined oil characterized by a low carbon residue and a light color and thereafter extracting the remainder of sorbed components with a polar solvent.

8,,A process for refining a mineral oil, comprising contacting said oil with a uniform, substantially microporous contact material having a particle size not less than about 30 mesh and in which the volume of pores having radii greater than about 100 angstrom units -is less than about 30 per cent of the total pore volume whereby the low viscosity, light-colored components of said oil are sorbed into the pores of said contact material, while the high viscosity, darkcolored components remain unsorbed, separating said contact material from said unsorbed components, heating said contact material containing sorbed components at a temperature between about 200 F. and about 600 F. for a period of from about 1 to about 5 hours and extracting the sorbed heat treated components with a paraifinic solvent to yield a refined oil of low carbon residue, high viscosity index and light color.

9. A process for refining a petroleum hydrocarbon mixture, comprising contacting said mixture in the liquid phase with a porous particleform contact material in which most of the pores are micropores and the volume of pores having radii greater than about 100 angstrom units is less than about per cent of the total pore volume and in which the particles are greater than about 60 mesh size to effect sorption of the less viscous, light-colored components of said mixture into the pores of said contact material, while leaving unsorbed the more viscous, dark-colored components, separating the unsorbed components from the contact material containing sorbed components, heating said contact material containing sorbed components to an elevated temperature greater than about 200 F. but insufficient to cause appreciable cracking of the components sorbed therein, selectively extracting said contact material with a parafiinic solvent to remove therefrom a refined product characterized by a low carbon residue and a light color, thereafter extracting the remainder of sorbed components with a polar solvent, heating the contact material and repeating the aforesaid steps by bringing the contact material obtained after said solvent extractions and heating into contact with a fresh charge of petroleum hydrocarbon mixture.

10. A process for refining a mineral oil, comprising sorbing the less viscous, light-colored components of said oil into the pores of a substantially microporous particle-form sorbent contact material, the particles of which are greater than about 30 mesh and in which less than 30 per cent of the total pore volume is occupied by pores having radii greater than about angstrom units, while leaving unsorbed the more viscous, dark-colored components of said oil, separating the unsorbed components from the contact material containing sorbed components, washing adhering unsorbed components from the surface of said contact material, heating said contact material containing sorbed components to an elevated temperature between about 200 F. and about 600 F. for a period of from about 1 to 5 hours, selectively extracting said contact material with a parafiinic solvent to remove therefrom a refined oil characterized by a low carbon residue and a light color, thereafter extracting the remainder of sorbed components with a polar solvent, heating the contact material and repeating the aforesaid steps by bringing the contact material obtained after said solvent extractions and heating into contact with a fresh charge of mineral oil.

ALEXANDER GREENTREE. DONALD A. HERMANSON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,294,779 Hyman Sept. 1, 1942 2,446,799 Winding Aug. 10, 1948 2,449,402 Lipkin et al Sept. 14, 1948 2,464,311 Hiatt et a1. Mar. 15, 1949 2,487,805 Hermanson Nov. 15, 1949 2,487,806 Hermanson et a1. Nov. 15, 1949 

1. A PROCESS FOR REFINING A PETROLEUM HYDROCARBON MIXTURE, COMPRISING CONTACTING SAID MIXTURE IN THE LIQUID PHASE WITH A POROUS PARTICLEFORM CONTACT MATERIAL IN WHICH MOST OF THE PORES ARE MICROPORES AND THE VOLUME OF PORES HAVING RADI GREATER THAN ABOUT 100 ANGSTROM UNITS IS LESS THAN ABOUT 30 PER CENT OF THE TOTAL PORE VOLUME AND IN WHICH THE PARTICLES ARE GREATER THAN ABOUT 60 MESH SIZE TO EFFECT SORPTION OF THE LESS VISCOUS, LIGHT-COLORED COMPONENTS OF SAID MIXTURE INTO THE PORES OF SAID CONTACT MATERIAL, WHILE LEAVING UNSORBED THE MORE VISCOUS, DARKCOLORED COMPONENTS, SEPARATING THE UNSORBED COMPONENTS FROM THE CONTACT MATERIAL CONTAINING SORBED COMPONENTS, HEATING SAID CONTACT MATERIAL CONTAINING SORBED COMPONENTS TO AN ELEVATED TEMPERATURE GREATER THAN ABOUT 200* F. BUT INSUFFICIENT TO CAUSE APPRECIABLE CRACKING OF THE COMPONENTS SORBED THEREIN AND THEREAFTER SOLVENT-EXTRACTING SAID SORBED HEAT TREATED COMPONENTS FROM THE PORES OF SAID CONTACT MATERIAL. 